Self-pressurized container having a convoluted liner and an elastomeric sleeve

ABSTRACT

Self-pressurized container which comprises a liner/sleeve assembly containing a thin, flexible radially expandable convoluted plastic liner, about 0.010 to about 0.020 inch think, inside an essentially cylindrical elastomeric sleeve. The liner is generally cylindrical, open at one end and closed at the other end, and comprises an outwardly turned flange and an upper sidewall adjacent to the open end and a convoluted portion comprising longitudinally extending convolutions which extend from the upper sidewall towards the closed end. The liner is formed in the convoluted state, and has memory so that it returns to the convoluted state when unstressed. The outside diameter of the liner, measured between diametrically opposite peaks of the convolutions when the liner is unstressed, exceeds the inside diameter of the elastomeric sleeve when unstressed. Both liner and sleeve expand radially outwardly when the liner is filled under pressure with product to be dispensed. The liner/sleeve assembly is capable of holding a substantial quantity of fluid product and of causing substantially all of said product to be dispensed. The top assembly of the container is similar to that of a conventional aerosol container, comprising a valve assembly with a metallic cup whose rim is crimped around a ring surrounding a central opening of a metallic dome, but with a part of the upper sidewall of the liner clamped between the cup and the dome ring as a gasket to form a fluid tight closure for the liner.

CROSS REFERENCE TO RELATED APPLICATION

Applicant under 35 USC 120 and 35 USC 365(c) claims the benefit of thefiling dates of earlier copending U.S. application Ser. No. 07/358,392,filed May 26, 1989 now abandoned and earlier copending PCT Internationalapplication PCT/US90/03062, filed May 25, 1990, which designates theUnited States. This application is a continuation-in-part of bothearlier applications.

TECHNICAL FIELD

This invention relates to self-pressurized containers for containing anddispensing of fluid materials.

BACKGROUND ART

Aerosol containers for containing and dispensing of fluid materials arewell known and widely used. Products sold in aerosol containers include,for example, foods such as whipped cream; toiletries such as shavingcream, deodorant and hair spray; and paints, just to name a few.Dispensing is accomplished with the aid of a propellant under pressure.Aerosol containers offer the advantages of convenience and nearlycomplete dispensing of the fluid product material from the container.Disadvantages of aerosol container include their limited operatingtemperature range and the fact the container must be held upright todispense properly.

A major concern over aerosol containers is the fact that the propellantsused and the pressures required present environmental hazards. Aerosolcans fall into one of two categories as follows: 1) where the productand the propellant mix, which is a standard aerosol container and 2)where the product and the propellant are kept separated and that isknown as a barrier pack. One of the concerns that exists with thebarrier pack container is that propellant is locked into the containerafter the product has been expelled, creating an extreme hazard in theincineration of that type of container because a cloud of propellant canbe formed if too many containers are crushed at the same time creatingan explosive situation. A point of fact is that the Recycle Energy plantin Akron, Ohio has had several explosions due to too many of the barrierpack aerosols being crushed prior to incineration.

One of the principal classes of propellants are the fluorocarbons andchlorofluorocarbons (CFCs). Recent environmental concern regarding theuse of these materials, and particularly the harmful effect on the ozonelayer of the upper atmosphere, has prompted a search for replacement. Infact, some major manufacturers of these materials have pledged to phaseout their production over the next decade or so. Another class ofpropellants are hydrocarbons, particularly the liquified petroleum gas(LPG) hydrocarbons such as butane and pentane. While these do not tendto deplete the ozone layer (as far as is known), they do present otherhazards because of their flammability. Also, there are certain hazardsin filling, transporting, storing and incineration of aerosol containersbecause of the high pressure required, no matter what propellant isused. These hazards are reflected in terms of costs, e.g., safetyprecautions in filling and handling, insurance costs, etc.

Self-pressurized containers have been suggested as an alternative toaerosol containers. Representative self-pressurized containers includethose shown and described in U.S. Pat. No. 4,387,833 to Venus, Jr. and4,423,829 to Katz. These references, which are rather similar in theirteachings, describe apparatus for containing and dispensing of fluidsunder pressure in which no propellant is used and in which the fluidmaterial to be dispensed is contained in a flexible plastic liner whichin turn is contained in (from the inside out) a fabric sleeve and anelastomeric sleeve, which surround the liner except for a small neckportion at the top. The liner (except for the neck portion) has aplurality of longitudinally extending folds. When the liner is filledunder pressure with the desired product, the entire assembly expandsradially. The liner, which has a star shaped configuration when foldedand not under pressure, is nearly circular in cross section when fullyexpanded. The elastomeric sleeve stores energy as a result of its radialexpansion. This stored energy in the sleeve causes fluid to be dispensedupon opening of the dispensing valve. The container assembly contractsradially and the liner becomes folded, as it is emptied.

A disadvantage of self-pressurized containers of this sort is that anappreciable quantity of product remains inside the liner when it hasbeen emptied as far as possible. This, of course, is costly. This may beattributable to the fact that the liners in the Venus and Katzstructures are formed (e.g., by blow molding) in a smooth, essentiallycylindrical configuration, and the folds or creases are then formedafterward. Since the preferred plastic materials have "memory", theliner seeks to return to the shape in which it is formed and resistsbecoming completely folded, which is essential to substantially completeexpulsion of the product.

A further disadvantage of the Venus and Katz structures lies in thevalve assembly at the top of the container. In this valve assembly, acylindrical wall of a valve body is joined solely to the neck portion ofthe liner, with no additional support structure.

The neck portion of the liner is made thicker than the rest of the linerand is designed to use only one valve assembly.

DISCLOSURE OF THE INVENTION

This invention according to one aspect thereof provides a reusable andrecyclable, self-pressurized container comprising:

(a) a radially expandable generally cylindrical flexible plastic lineropen at one end and closed at the other end, said liner being ofsufficient thickness to be self-supporting in the unstressed state andhaving upper sidewall means adjacent to the open end and regularlyconvoluted portion comprising a plurality of longitudinally extendingconvolutions extending from upper sidewall means toward the closed end,said liner having an outwardly turned flange at the open end thereof;

(b) an essentially cylindrical elastomeric sleeve open at both ends andsurrounding at least a major portion of the liner in tight-fittingrelationship, the normal inside diameter of said sleeve beingsubstantially smaller than the exterior diameter of the liner in itsfolded state; and

(c) a housing comprising a sidewall and an essentially rigid annulardome, said dome having a central opening and a ring surrounding saidopening; and

(d) a valve assembly including a valve for dispensing fluid materialfrom the interior of said plastic liner, an essentially rigid cup havingan upstanding sidewall, and a vertical tubular stem for discharge ofsaid fluid material, the upper portion of the sidewall of said cupincluding said flange being crimped against the ring of said dome withthe open end of said liner being clamped therebetween.

This invention according to another aspect thereof provides a fluiddispensing assembly for a self-pressurized container, comprising aradially expandable liner and an elastomeric sleeve surrounding the sameas above described.

This invention according to a further aspect provides a method formaking a self-pressurized container as above described, which comprises:

(a) molding a moldable material into a generally cylindricalself-supporting flexible liner open at one end and closed at the otherend and having, as molded upper sidewall means adjacent to the open end,an outwardly turned flange at the open end and a regularly convolutedportion comprising a plurality of regularly spaced convolutionsexpanding longitudinally from the upper sidewall means toward the closedend;

(b) inserting said liner into an elastomeric sleeve having an insidediameter substantially smaller than the exterior diameter of the linerin its folded state and an axial length less than that of the liner, sothat the upper sidewall means of the liner protrudes from the sleeve;

(c) placing an annular essentially rigid dome having a central openingand a ring encircling said opening so that said ring is in touchingengagement with the outside surface of the upper sidewall means;

(d) placing a valve assembly which includes a metal cup having enoughstanding sidewall so that said sidewall is in contact with the insidesurface of the upper sidewall means of the liner;

(e) crimping the upper edge of the sidewall means of said cup againstsaid ring, with the part of the upper sidewall means of said linerclamped therebetween as a gasket material to form a fluid tight sealbetween said cup and said liner; and

(f) assembling any remaining housing components to form said container.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 is an elevational view, with parts shown in longitudinal section,of a container according to this invention.

FIG. 2 is an elevational view of a liner according to this invention inits normal or folded state.

FIG. 2A is a fragmentary elevational view of a modified form of lineraccording to this invention in its normal or folded state.

FIG. 3 is an elevational view of a liner according to this invention inits expanded state.

FIG. 4 is a cross-sectional view, taken along line 4--4 of FIG. 2, of aliner of this invention in its folded state.

FIG. 5 is a cross-sectional view, taken along line 5--5 of FIG. 3, of aliner of this invention in its expanded state.

FIG. 6 is an elevational view, with part shown in longitudinal section,of a sub-assembly comprising a fluid dispensing assembly (or aliner/sleeve assembly) and a dome.

FIG. 7 is a fragmentary elevational view, with parts shown in section,of a portion of the subassembly of FIG. 6, shown in a later stage ofassembly.

FIG. 8 is a vertical sectional view, taken along line 8--8 of FIG. 7,showing an enlarged detailed, not to scale, joint among the dome, linerand valve assembly of this invention.

BEST MODE FOR CARRYING OUT THE INVENTION

This invention will now be described in detail with particular referenceto the best mode and preferred embodiment thereof.

The container of this invention as a whole is shown in FIG. 1. Referringto FIG. 1, container 10 is a self-pressurized container for dispensingof fluid materials, which comprises a fluid dispensing assembly 12including an expandable liner 14 having a major portion which ispleated, and an elastomeric sleeve 16 surrounding a major portion of theliner in tightfitting relationship; a housing which comprises an annulardome 18, a cylindrical sidewall or outside shell 20, and a bottom wall22; and a valve assembly 24 (see FIG. 8) which comprises a cup 26 havinga central opening, a vertical tubular stem 28 extending through thecentral opening of cup 26 for discharge of fluid product from liner 14,a collar 29 surrounding the lower portion of stem 28 just above cup 26,a valve 30 and a cap 31 (shown in phantom lines in FIG. 1) which isoptional. Valve 30 may be a conventional spring pressed reciprocatingvalve similar to those used in aerosol containers.

FIG. 1 shows liner 14 and sleeve 16 in their normal position, i.e., whenliner 14 is empty. When liner 14 is pressurized and filled with productto be dispensed, the sleeve 16 assumes the contour shown in phantomline.

The liner 14 will now be described in detail with particular referenceto FIGS. 2-5. Referring now to FIG. 2, liner 14 is an elongated,generally cylindrical, radially expandable but longitudinallyinextensible, flexible plastic article, open at one end (the upper end)and closed at the other end (the lower end), and has upper sidewallsmeans (or upper portion) 32 adjacent to the open end, and an elongated,regularly convoluted portion 34 which extends from the upper sidewallmeans 32 to the closed end. The lower part of convoluted portion 34 istapered inwardly, and the liner 14 terminates in a blunted or roundedpoint 36 at its closed end.

The upper sidewall means 32 of liner 14 is devoid of pleats andcomprises a frustoconical flange 38 at the open end, a pair ofconcentric cylindrical sections 40 and 42, the former being of largerdiameter than the latter and being disposed closer to the open end, anda frustoconical transition section 44 linking the cylindrical sections40 and 42. The smaller cylindrical section 42 may be provided with beads46 as shown in FIG. 2A. if desired for gripping, as will be hereinafterdescribed. However, beads 46 are not necessary for good frictionalengagement between the liner 14 and the sleeve 16, and may be omitted.Cylindrical section 42 may be of very short axial length and can beomitted entirely, so that frustoconical section 44 is adjacent to theupper end of the convoluted portion 34.

Convoluted portion 34 comprises a plurality of longitudinally extendingfolds or convolutions 48, best seen in FIG. 4. These convolutions formalternating ridges 50 and valleys 52. The ridges and valleys are creasedforming a permanent pleat. The ridges and valleys (except the endportions thereof) define a pair of concentric right circular cylinders.The ridges taper toward upper sidewall means 32 at the upper end ofconvoluted portion 34. This aids in avoiding trapping of material to bedispensed in this region. The valleys may either taper or not at theupper end of the convoluted portion 34. Both the ridges and valleystaper toward point 36 at the lower end. Thus, the greater part of theconvoluted portion 34 (excluding the upper and lower ends thereof) iscylindrical and of uniform diameter. This cylindrical part of convolutedportion 34 constitutes a major portion of the overall length of liner14. The contours of the peaks of pleats 48 when the liner 14 is in itsnormal or empty (i.e., non-pressurized) state may be seen in FIG. 2.FIG. 3 shows that contours of pleats 48 when the liner 14 is in itsexpanded or pressurized state (i.e., when filled with product to bedispensed).

The depth of convolutions or pleats 48 is essentially uniform in thecylindrical middle part of convoluted portion 34. The depth of thepleats 48 decreases at either end of convoluted portion 34 as oneapproaches either the upper sidewall means 32 (at the upper end) or thepoint (at the lower end). The depth of pleats 48 should be greater atthe lower end than at the upper end for any given inner circle diameter(representing the diameter of the circle that connects the valleys). Itis believed that this is beneficial in obtaining substantially completeexpulsion of product from liner 14, as will be discussed in greaterdetail later.

The inner circle diameter of the convoluted portion 34 is preferablyequal to or slightly greater than the inside diameter of cylindricalsection 43 so that this cylindrical section 42 forms a neck portion ofliner 14.

While the convoluted portion 34 as shown is a generally cylindricalconfiguration, it may assume other configurations, e.g., ellipsoidal orspherical. In any case, the preferred configurations are surfaces ofrevolution, and in all cases the convoluted portion has regularlongitudinally extending convolutions, which are permanent pleats.

Liner 14 is made of a flexible plastic material, which may be eitherelastomeric or nonelastomeric, preferably non-elastomeric. A preferredmaterial is high density polyethylene (HDPE); other suitable materialsinclude polyamide and "Barex" 218, which is an acrylonitrile availablefrom British Petroleum. Liner 14 is a free standing member, i.e., it isnot integrally joined to any other part or component of the container10. Liner 14 is flexible over its entire length, but is stiff enough tobe self-supporting.

The liner may be of any suitable thickness, typically about 10 to 20mils (0.010 to 0.020 inch) preferably about 0.012 to 0.018 inch. Exceptfor the tapered portion near point 36, the liner should be ofsubstantially uniform thickness over its entire length. (Minorvariations in thickness, up to about 0.004 inch between the greatest andleast thickness, are acceptable). The liner 14 is radially expandable byvirtue of its folds or convolutions 48, even when it is made of anon-elastomeric material. Liner 14 is substantially inextensible in thelongitudinal direction. A non-elastomeric liner having a thickness of10-20 mils is inherently flexible; for example, it can be flexed or bentby hand. It is also inherently compressible, i.e., it can be squeezed inthe radial direction by finger pressure applied by a person between thethumb and forefinger. At the same time, this thickness is sufficient sothat the liner is selfsupporting, i.e., capable of holding the folded orconvoluted shape shown in FIGS. 1, 2, 4 and 6 of the drawings when notunder pressure and (because the plastic material forming the liner hasmemory) returning to that shape when stress is removed. When a fluidunder pressure is introduced into the liner 14, it expands, assuming theconfiguration shown in FIGS. 3 and 5. The circumference or perimeter ofthe liner in its expanded form is nearly circular as may be seen in FIG.5. FIG. 5 may represent an expanded liner 14 of this inventionapproximately in its actual size (typically 1.75 inch diameter)(orsomewhat larger than actual size, as shown). The outer diameter of theliner in its folded form (measured between two diametrically oppositeridges 50) is about one-half the diameter in the expanded form.

The liner may be formed by conventional plastic molding techniques,preferably by blow molding. The liner is molded in its folded form asshown in FIGS. 2 and 4. Since the material forming the liner has memory,the liner will return to the folded form shown in FIG. 2 when nopressure or other stress is applied. This is important in order that theliner will have maximum effectiveness in expelling substantially theentire quantity of product contained in liner 14.

Liner 14 is placed inside a cylindrical elastomeric sleeve 16, whichfurnishes the energy required to dispense the product from liner 14,forming fluid dispensing assembly (or liner/sleeve assembly) 12. Sleeve16 is a tube, open at both ends, which stores energy as liner 14 isfilled with product under pressure and which releases that energy asproduct is dispensed from liner 14. The wall thickness of sleeve 16 mustbe sufficient for this purpose. Sleeve 16 in its unstressed state is atube of uniform diameter over its entire length. The inside diameter ofsleeve 16 in its unstressed state is substantially smaller than theoutside diameter of liner 14 in its folded state. (The outside diameterof liner 14 in its folded state is the diameter as measured between twodiametrically opposite ridges). The diameter of sleeve 16 is expandedslightly over most of its length as shown in FIG. 6, after insertion ofliner 14. The axial length of sleeve 16 is less than that of liner 14.The upper sidewall means 32 of the liner protrudes from one end of thesleeve 16 and the tapered lower end of the liner (near point 36)protrudes from the other end of the sleeve, when the liner/sleeveassembly 12 is not under pressure. When the liner 14 is filled withproduct under pressure, sleeve 16 expands radially and elongates in theaxial direction, assuming the outline shown in the phantom line inFIG. 1. The liner 14 expands radially, from the folded state shown inFIGS. 2 and 4 to the expanded state shown in FIGS. 3 and 5, whileremaining at substantially its original length. When the liner 14 andsleeve 16 are so expanded, the lower end of sleeve 16 extends beyond thepoint 36 of liner 14, as may be seen in FIG. 1. Sleeve 16 should be atleast about 25 percent longer in its pressurized and expanded state thanin its normal or relaxed state when the aspect ratio of the liner 14(which is the ratio of its length to its diameter in the expanded state)is at least 3. The percentage elongation required increases as theaspect ratio decreases. The liner will usually have an aspect ratio ofat least 3 when its capacity is 12 ounces (340 grams) or less. Smalleraspect ratios are frequently preferred in larger containers.

The preferred elastomeric material for sleeve 16 is a synthetic rubber,and in particular Natsyn rubber. Natsyn rubber is cis-1,4-polyisoprene.A desirable characteristic of Natsyn rubber is that it is able to hold ahigh pressure per gram of material. Also, Natsyn rubber has less "dieswell" than most rubbers, and considerably less than that of naturalrubber. Rubbers tend to expand or swell dimensionally as they come outof the die, and "die swell" is the measure of this degree of swelling.Also, Natsyn rubber possesses the ability to elongate as well as expandradially when pressurized. The elastomeric material used to form sleeve16 should exhibit both elongation and radial expansion when pressurized.The percentage elongation required will vary somewhat depending upon theaspect ratio of the sleeve 16, is noted above. Since some relativelongitudinal movement between the sleeve and the liner occurs duringfilling and dispensing, as is apparent from FIG. 1, it may be desirableto include a lubricant additive in the elastomer composition formingliner 16, as is apparent to those skilled in the art.

Liner/sleeve assembly 12 preferably does not include any structuralelements other than liner 14 and sleeve 16, and so preferably consistsessentially of the liner 14 and the sleeve 16.

All references to size, dimensions and shape of liner 14 and sleeve 16refer to the normal or unstressed state, i.e., when the liner and sleeveare not assembled into a liner/sleeve assembly 12 and each is surroundedby air at atmospheric pressure, unless otherwise stated.

Referring now to FIG. 7, dome 18 is annular, may be bell-shaped asshown, has a central opening with a ring 56 around this central openingand also has a lip 58 extending around its circumference or outer edgeand forming a locking device to accept an outside shell. Configurationof dome 18 may be substantially the same as that of the dome in aconventional aerosol container. Dome 18 is preferably metallic, and inany case should be essentially rigid and of sufficient strength topermit crimping of the outer edge or lip of cup 26 around ring 56, aswill be hereinafter described. Similarly, cup 26 is preferably metallicand should be essentially rigid and sufficiently strong and resilient topermit crimping.

FIG. 8 shows the top assembly 60 of a container 10 according to thisinvention, with parts broken away and parts drawn to an exaggeratedscale. Dome 18 has a central opening and a ring 56 extending around thecentral opening as previously explained. Cup 26 comprises a flatcircular disk-like portion 62 with a central opening for dispensing stem28 and collar 29, and an upstanding sidewall 64 which is a surface ofrevolution. Sidewall 64 terminates at its upper (or outer) end in a rim66. The upper edge or rim 66 of sidewall 64 is crimped against ring 56,with the upper part of the upper sidewall means 32 of liner 14 clampedbetween the crimped portion 66 of top sidewall 64 and the ring 56 ofdome 18. This affords a fluid tight closure of the upper or open end ofliner 14. Cup 26, stem 28, collar 29 and valve 30 together form valveassembly 24.

The configuration of the entire top assembly 60 of container 10,including valve assembly 24 and ring 18, but excluding liner 14, isquite similar to that of a conventional aerosol container, the exceptionbeing that the outside edge will accept and lock an outside shell of anon-metallic material. The top assembly herein is quite different fromthose shown in the above referenced U.S. Pat. Nos. 4,387,833 and4,423,829.

A container can, according to this invention, may be assembled asfollows:

First, a liner 14 in its normal folded state, as shown in FIG. 2, isinserted into a sleeve 16, also in its normal state, to form a fluiddispensing assembly (or liner/sleeve assembly) 12 as shown in FIG. 6. Alubricant may be applied to either the outside surface of the liner orthe inside surface of the sleeve to facilitate insertion. (This isusually not necessary when a lubricant additive is included in thecompound forming sleeve 16). The upper end of sleeve 16 surrounds theupper portion, of liner 14, and preferably overlies cylindrical section42 and is in frictional engagement therewith. The tapered end 36 ofliner 14 extends beyond the adjacent end of sleeve 16. The gripper rings46 (when present) grip the inside of the sleeve 16 near its upper end,as an aid in retaining the liner inside the sleeve. Normally, however,frictional engagement between sleeve 16 and the upper sidewall means 32(and particularly cylindrical section 42 thereof) of liner 14 issufficient so that rings 46 are not necessary.

Next, dome 18 is put in place. This is done by putting the liner/sleeveassembly, beginning at the end having the closed end 36 of line 14,through the central opening of the dome 18. This will bring the ring 56into engagement with the larger cylindrical section 40 of upper sidewallmeans 32 of liner 14, as shown in FIG. 6. The outside diameter ofsection 40 is essentially the same as the diameter of the centralopening of dome 18. The liner/sleeve assembly 12 is then gently pulleduntil ring 56 is in contact with flange 38 of liner 14.

Third, the valve assembly 24 with the sidewall 64 of cup 26 (not yetcrimped) is put in place so that the upper edge or rim of cup sidewall64 is substantially abreast of flange 38. Then the upper part of cupsidewall 64 is crimped against the ring 56 of dome 18, clamping theupper part of the upper sidewall means 32 of liner 14 (including flange38 and part of cylindrical section 40) in between the cup sidewall 64and the dome ring 56. The upper part of cup sidewall 64 is formed into alip 66 in the crimping process.

Finally, any remaining housing components, such as outer shell orsidewall 20 and bottom wall 22 (which may be pre-assembled), areassembled into place. This may be done by conventional means.Alternatively, this sidewall 20 and bottom wall 22 may be preassembledwith dome 18, in which case the entire assembly shown in FIG. 6, i.e.,liner/sleeve assembly 12 and top assembly 60, including dome 18 andvalve assembly 24, may be inserted into this housing pre-assembly.

A container 10 according to this invention is filled with a fluidproduct by pumping the fluid product in through stem 28 into liner 14,and continuing such pumping until the liner expands to the positionshown in FIG. 5. The sleeve 16 expands radially simultaneously with theliner 14. Radial expansion will ordinarily commence in the lower portionof liner 14 (e.g., just above the tapered lower part of convolutedportion 34 and remote from the upper end of sleeve 16). Sleeve 16 alsoelongates axially as the liner 14 is filled. No slippage between thesleeve and the liner occurs at the upper end of the sleeve, but theremainder of the sleeve elongates. The length of liner 14 remainssubstantially the same, whether liner 14 is folded (as in FIG. 2) orexpanded (as in FIG. 3). Expansion of the sleeve 16 causes it to storeenergy. When the liner/sleeve assembly 12 is in its fully expanded state(and during expansion as well), the stress exerted by the fluid productis borne by the sleeve 16. The liner 14 is substantially unstressed andso is capable of withstanding the application of pressure by the fluidproduct contained therein, despite its thinness.

A user who wishes to dispense product from container 10 then causes thevalve 30 to open in a conventional way, e.g., by tilting or depressingstem 28. When the user wishes to stop the flow of product, he or shelets go of stem 28, allowing it to return to its upright position,whereupon valve 30 closes and flow of product stops. This can continueuntil the product is exhausted. The motive power for dispensing isfurnished by the energy stored in sleeve 16. As product is dispensed,the liner 14 and the sleeve 16 gradually return to their original(unstressed) shape as shown in FIG. 6 reaching that shape whensubstantially all of the product has been dispensed. The upper end ofsleeve 16 remains in position surrounding the upper portion of liner 14with no slippage in this area as the liner size sleeve assembly 12returns to its normal position. The pressure curve of sleeve 16 herein(i.e., the ratio of either percentage of radial expansion or percentageelongation to pressure applied) is substantially flat.

Substantially complete dispensing of the product is possible, since theliner 14 by virtue of memory returns to its folded position shown inFIGS. 2 and 4; furthermore, sleeve 16 contains enough stored energy,even when the liner sleeve assembly has nearly returned to its normalposition (FIG. 6), to expel product.

The container of this invention has several advantages over conventionalaerosol containers. First, no propellant is required. The safety andenvironmental hazards associated with aerosol propellants areeliminated. Secondly, filling and storage are at lower pressures than isthe case in the conventional aerosol container. Filling of a containerof this invention is less costly than filling of an aerosol container,because the costs of necessary safety equipment and insurance costs areboth reduced. Similarly, insurance costs during transportation are less.Finally, the container of this invention can be incinerated safely; itis at virtually atmospheric pressure when exhausted and therefore willnot explode and there are no toxic combustion products. The containerherein has the additional advantage of being refillable or reusable andhas recyclable components. A container of this invention has theadvantage over previously known self-pressurized containers in that agreater proportion of the product contained therein is expelled.Expulsion of product is substantially complete in containers of thisinvention, while appreciable quantity of product remains in previouslyknown self-pressurized containers when the container has been emptied asfar as possible. Furthermore, the fluid tight joint between valveassembly and liner is superior to the joint between the valve assemblyand liner in previously known self-pressurized containers, such as thosein the Venus and Katz patents. This invention has the advantage ofmaterial versatility in the liner, and because a standard aerosol valveis being used, thousands and thousands of combinations are availablebetween valve and spray head design.

While this invention has been described with reference to the best modeand preferred embodiment thereof, it is understood that this descriptionis by way of illustration and not by way of limitation.

What is claimed is:
 1. A fluid dispensing assembly for aself-pressurized container, said assembly comprising:(a) an elongatedradially expandable generally cyclindrical flexible plastic liner openat one end and closed at the other end, said liner being of sufficientthickness to be self-supporting in the unstressed state and having uppersidewall means adjacent to the open end and a regularly convolutedportion comprising a plurality of longitudinally extending convolutionsextending from said upper sidewall means towards the closed end, saidliner having an outwardly turned flange at the open end thereof, saidliner having an essentially uniform thickness in the range of about0.010 inch to about 0.020 inch over its entire length except optionallyadjacent to the closed end; and (b) an essentially cylindricalelastomeric sleeve open at both ends and surrounding at least a majorportion of said liner in close fitting relationship, with no structuralelement between said liner and said sleeve, the normal inside diameterof said sleeve being substantially smaller than the exterior diameter ofthe liner in its folded state, said sleeve being free to elongateaxially and having an axial length at least about 25% greater in thepressurized state than in the non-pressurized state.
 2. A fluiddispensing assembly according to claim 1 wherein the normal insidediameter of said sleeve is substantially less than the expanded diameterof said liner.
 3. A fluid dispensing assembly according to claim 1wherein the axial length of said sleeve in the unstressed state is lessthan that of said liner and the axial length of said sleeve in thepressurized state is greater than that of said liner.
 4. A fluiddispensing assembly according to claim 1 wherein said convoluted portioncomprises an essentially cylindrical middle portion and a tapered bottomportion adjacent to said closed end and disposed below said middleportion, said upper sidewall means and said essentially cylindricalportion being of essentially uniform thickness in the range of about0.010 inch to about 0.020 inch.
 5. A fluid dispensing assembly accordingto claim 1 further including a lubricant applied to one of the insidesurfaces of said sleeve and the outside surface of the liner.
 6. A fluiddispensing assembly according to claim 1 wherein said liner is formed inthe folded state wherein said convolutions are present and has memory,whereby said liner returns to the folded state when unstressed.
 7. Afluid dispensing assembly according to claim 6 wherein said liner isnon-elastomeric.
 8. A fluid dispensing assembly according to claim 6,said fluid dispensing assembly consisting essentially of said liner andsaid sleeve.
 9. A self-pressurized container comprising:(a) aliner/sleeve assembly comprising (1) an elongated radially expandablegenerally cylindrical flexible plastic liner open at one end and closedat the other end, said liner being of sufficient thickness to beself-supporting in the unstressed state and having upper sidewall meansadjacent to the open end and a regularly convoluted portion comprising aplurality of longitudinally extending convolutions extending from saidneck portion toward the closed end, said liner having an outwardlyturned flange at the open end thereof, said liner having an essentiallyuniform thickness in the range of about 0.010 inch to about 0.020 inchover its entire length except optionally adjacent to the closed end; (2)an essentially cylindrical elastomeric sleeve open at both ends andsurrounding at least a major portion of said liner in tight fittingrelationship, with no structural element between said liner and saidsleeve the normal inside diameter of said sleeve being substantiallysmaller than the exterior diameter of the liner in its folded state,said sleeve being free to elongated axially and having an axial lengthat least about 25% greater in the pressurized state than in thenon-pressurized state; (b) a housing comprising a sidewall and anessentially rigid annular dome, said dome having a central opening and aring surrounding said opening; and (c) a valve assembly including avalve for dispensing fluid material from the interior of said plasticliner, an essentially rigid cup having an upstanding sidewall and avertical tubular stem for discharge of said fluid material, the upperportion of the sidewall of said cup including said flange being crimpedagainst the ring of said dome with the open end of said liner beingclamped therebetween.
 10. A container according to claim 9 wherein saidcup and said dome are metallic.
 11. A container according to claim 9wherein said liner is non-elastomeric.
 12. A container according toclaim 9 wherein said liner is formed in the folded state wherein saidconvolutions are present and has memory, whereby said liner returns tothe folded state when unstressed, and said convolutions form peaks andvalleys wherein a crease is formed as a permanent pleat at each peak andvalley.
 13. A container according to claim 9 wherein the normal axiallength of said sleeve is less than that of said liner and the expandedaxial length of said sleeve is greater than that of said liner.
 14. Acontainer according to claim 9 wherein said convoluted portion comprisesan essentially cylindrical middle portion greater than half the totallength thereof and a tapered bottom portion adjacent to said closed endand disposed below said middle portion, said upper sidewall means andsaid essentially cylindrical portion being of essentially uniformthickness in the range of about 0.010 inch to about 0.020 inch.
 15. Acontainer according to claim 9, further including a lubricant applied toone of the inside surface of said sleeve and the outside surface of theliner.
 16. A method for making a self-pressurized container whichcomprises:(a) molding a moldable material essentially the same thicknessthroughout, into an elongated generally cylindrical self-supportingflexible liner open at one end and closed at the other end and having,as molded upper sidewall means adjacent to the open end, an outwardlyturned flange at the opened and a regularly convoluted portioncomprising a plurality of longitudinally extending convolutionsextending from said upper sidewall means towards the closed end saidliner as molded having an essentially uniform thickness in the range ofabout 0.010 inch to about 0.020 inch over its entire length exceptoptionally adjacent to the closed end thereof; (b) inserting said linerinto an elastomeric sleeve with no structural element between said linerand said sleeve, said sleeve having an inside diameter substantiallysmaller than the exterior diameter of the liner in its folded state andan axial length less than that of said liner, so that the upper sidewallmeans and the closed end of said liner protrude from said sleeve whenboth said liner and said sleeve are in the non-pressurized state, saidsleeve being free to elongate axially and having an axial length atleast about 25% greater in the pressurized state than in thenon-pressurized state; (c) placing an annular essentially rigid domehaving a central opening and a ring encircling said opening so that saidring is in touching engagement with the outside surface of the uppersidewall means; (d) placing a valve assembly which includes a metal cuphaving a bottom portion and an upstanding sidewall means, so that saidcup is in contact with the inside surface of the upper sidewall means ofsaid liner; (e) crimping the upper edge of the sidewall means of saidcup against said ring, with the part of the upper sidewall means of saidliner clamped therebetween as a gasket material to form a fluid tightseal between said cup and said liner; and (f) assembling any remaininghousing components to form said container.
 17. A method according toclaim 16 wherein said convoluted portion comprises an essentiallycylindrical middle portion and a tapered bottom portion adjacent to saidclosed end and disposed below said middle portion, said upper sidewallmeans and said essentially cylindrical portion being of essentiallyuniform thickness in the range of about 0.010 inch to about 0.020 inch.18. A method according to claim 16 wherein a lubricant is applied to theinside surface of said sleeve or the outside surface of said liner priorto insertion of said liner.